Facile fabrication of MIL-96 as coating fiber for solid-phase microextraction of trihalomethanes and halonitromethanes in water samples

Abstract

Trihalomethanes (THMs) and halonitromethanes are the two most dominant categories of volatile disinfection by-products that pose considerable public health concerns. The pretreatment and determination methods of THMs in low concentrations, particularly trichloronitromethane (TCNM), have always been the focus of researchers. Metal-organic frameworks, which are effective adsorbents, have considerable potential for solid-phase microextraction (SPME) because of their tuned pore structure, large surface area, and high thermal and chemical stabilities. In this study, MIL-96 was successfully fabricated and developed as a coating fiber for SPME of THMs and TCNM in water samples. Several extraction parameters (i.e., extraction temperature, extraction time, stirring rate, pH, and ionic strength) and desorption parameters (i.e., temperature and time) were investigated and optimized in detail. Ionic strength, extraction temperature, and pH/desorption temperature were identified as key factors that affected the SPME efficiencies of THMs and TCNM. The developed method under optimal conditions obtained wide linearity (0.02–50 µg/L), low limits of detection (0.0030–0.0110 µg/L), and high enrichment factors (81–1181) for detecting THMs and TCNM. The spiked recoveries (1 and 10 µg/L) and relative standard deviations ranged from 81.0% to 109.9% and from 3.92% to 10.10%. Notably, the developed SPME method could overcome thermal degradation and showed excellent performance for TCNM. These results indicated the applicability of MIL-96 as coating fiber.